Apparatus for producing ions



June 9, 1931. GODDARD 1,809,115

APPARATUS FOR FRODUCING IONS Filed July 16, 1926 Pile!!! Tits-=9, 1931 UNITED STATES 3031mm 3. GODDARD, OF woms'mn, MASSACHUSETTS mar-am I 08 PRODUCING IONS Application Med Jul; 10, me. lerlal I0. 1888?.

This invention relates to apparatus having electrodes which emit ions consisting of charged atoms or molecules, or groups of atoms and molecules rather than electrons.

l One important ob ect of my invention is to Erovide an apparatus of this general type so esigned that it may be continuously operated and that the sup 1y of non-ionized material may be replem ed without inter- 10 ruptin the operation of the apparatus.

An or object of the invention is to provide apparatus wherein a substance in the non-ionized state may be introduced at one side of a relatively thin electrode, or an electrode havin a relatively thin wall portion,

into which electrode or wall ortion said material penetrates and from w ch it is finally liberated as ions at the other side thereof.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularl pointed out in the appended claims.

forms of the invention are shown in the drawings in which Fig. 1 1s a horizontal sectional v1ew through one form of my improved apparatusfig. 2 is a vertical sectional view, taken along the line 2-2 in Fi 1;

Fig. 3 is a sectional evation of a mod:- fied construction; and

Fi 4 shows a further sli ht modification. Ro er-ring to Figs. 1 an 2 in which a tubular electrode is emplo ed, I have shown the electrode as preferab y consisting of a thin platinum tube mounted a glass casing 11 and provided with terminals 12 and 13 through which a heating current may be supplied to the electrode 10 from a battery 14. This electrode acts as an anode and is advantageously employed in obtaining positive ions from the alkali metals such as potassium. The casing 11 also encloses a cathode which may be of any suitable form such as the hollow brass cylinder 15 which is shown in the drawings. A definite difi'erence in potential between the anode 10 and the cathode 15 is maintained by a suitable current generator such as a battery 16. A

stop cock17 is provided through which the caslng 11 ma be exhausted.

- In the pre erred form of my apparatus, I have also provided one or more supply chambers 18, 18, each containing a portion of the metal 19 to be ionized, which may be introduced into the chamber by removing a sto per 20. The supply chamber ma then exhausted through a stop cock 21, a r which communication with the electrode 10 in the casing 11 may be established by opening a second stop cock 22.

A heating coil 23, or any other convenient source of heat, is provided for vaporizing the metal 19 and the metallic vapor thus formed is conducted through the stop cock 22 to the inside of the platinum tube or electrode 10, where it is taken up by the latinum which it gradually penetrates, fina being liberated therefrom in the form O POSitIVG ions :t l31c charged outer surface of the platinum By using a second supply chamber 18, the apparatus may be operated continuously as long as desired, without interrupting the o eration thereof or substantially changing t e degge of vacuum in the casing 11.

18 second supply chamber 18 contains a supply of potassium or other alkali metal 19', w ich may be placed therein by removing the stopper 20". Air may be exhausted from the chamber 18" throu h the stop cook 21" and communication wit the casin 11 is established b opening the stop coc 22, all as revious y described. A separate heating coi 23' is also preferably provided. By using the supply chambers 18 and 18 alternately, the operation of the a paratus may be continued indefinitely, fr metal being placed in one supply chamber while the other chamber is operatively connected to the casing 11 and electrode 10.

This advantage of continuous operation of the apparatus herein described is not possessed by the apparatus heretofore commonly used, in which the electrodes consist of filaments or wires which are covered with a coating of a chemical compound or combination of elements which contain the substance to be ionized. Such electrodes, when exhausted of ionizable material, must be replenished with a fresh coating of the chemical point or mixture, which replenishment necessitates a complete interruption of the operation of the apparatus.

A particular advantage of my invention, as herein described, lies in the fact that ions of a material having a low boilin point may be discharged from the electro e at a muc higher temperature than could be employed if the ionizable substance were merely coated or deposited on the outer surface of the electrode. This higher temperature greatly decreases the proportion of uncharged atoms which will be emitted from the electrode.

While the apparatus shown and described in Figs. 1 and 2 has been found very satisfactory, the essential features of my invention maybe embodied in substantially differout form. In Fig. 3, I have shown the continuously acting electrode as made in the form of a thin plate or sheet 30 mounted in one side of a tubular support 31 within a vacuum casing 32. Heating of this thin plate electrode may be obtained by concentrating radiant energy R upon the electrode instead of by the use of electric current.

The cathode 35 may be of any suitable form connected electrically with the anode 30 through a battery 36. A continuous supply of metal to be ionized may be provided for the purpose shown in Fig. 3 by the use of one or more supply chambers (not shown) as in the previous form. The potassium vapor or other material supplied to the tube 10 (Fig. 1), or to the casing 31 (Fig. 3), may supplied at either high or low pressure as may be desired.

The partition or wall of the electrode ma consist of more than one layer of material: Thus the platinum tube 10 1n Figs. 1 and 2 may be covered on the outside with a coating of metal or chemical compounds such as is indicated at 40 in Fig. 4 and such as has been previously used for coating electrodes. One such material is potassium oxide which is preferably used when potassium is the metal to be ionized. This arrangement has the advantage that the ions are liberated at a comparatively low temperature compared with that required when a simple metallic electrode is used and it also has the advantage that the covering material does not become exhausted as in the usual form of apparatus but is apparently replenished from within the tube or behind the plate from the metallic vapor supplied thereto.

While the apparatus has been particularly described as applied to the production of positive ions, many features thereof are also applicable to the production of negative ions.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed otherwise than as set forth in the claims, but what I claim is 1. Apparatus for continuously producing ions comprising a vacuum casing, a cathode in said casing, an electrode mounted in said casing and having a relatively thin wall portion, and means to continuously supply ionizable material at one side of said wall portion, the ions to be liberated at the opposite side of said wall portion after penetrating through the material thereof, and means for replenishing said ionizable material from time to time during the continued operation of the machine.

2. Apparatus for continuously producing positive ions comprising a vacuum casing forming an outer cathode chamber, a tubular metallic electrode mounted within said casin and forming an inner vapor receiving cham er separated by the metallic wall of said tubular electrode from said outer chamber, said electrode being, a cathode in said casing, adapted to be heated and to be maintained at a definite potential, and means se arate and additional to said tubular electro e effective to continuously supply metallic vapor to the inside of said tubular electrode.

3. Apparatus for continuously producing positive ions comprising a vacuum casing, a cathode in said casing, a tubular metallic electrode in said casing adapted to be heated and to be maintained at a definite potential, and means to continuously supply metallic vapor to the inside of said tubular electrode, said latter means comprising a supply chamber having a valved connection with said tubular electrode and having provision for filling and exhausting said chamber while shut off from said electrode.

4. Apparatus for continuously producing positive ions comprising a vacuum casing, a cathode in said casing, a tubular metallic electrode in said casing adapted to be heated and to be maintained at a definite potential, and means to continuously supply metallic vapor to the inside of said tubular electrode, sald latter means comprising a pair of supply chambers each having a valved connection with said tubular electrode and each having provision for filling and exhaustion of said chamber while shut off from said electrode, said chambers being alternately operable during the continued operation of said electrade.

5. Apparatus for continuously producing ions comprising a vacuum casing, a cathode in said casing an electrode mounted in said casing and having a relatively thin wall portion, and means to continuously supply ionizable material at one side of said wall portion, the ions produced from said ionizable material on one side of said wall portion be ing thereafter liberated at the opposite side of said wall portion after penetrating through the thickness and substance of said wall ortion of said electrode, said electrode also aving a coatin of additional ionizable material applied to t e liberating surface thereof.

6. Apparatus for continuously producing positive ions comprising a vacuum casing, a cathode in said casing, a tubular metallic electrode in said casing ada ted to be heated and to be maintained at a efinite potential, and means to continuously supply metallic va or to the inside of said tubular electrode, said latter means comprising a supply chamher having a valved connection with said tubular electrode and having provision for filling and exhausting said chamber while shut off from said electrode, and also having rovision for vaporizin the metallic ionizable material containe within said supply chamber.

ROBERT H. GODDARD. 

